Rectangular spring assemblies of the continuous coil type conventionally include continuous coil springs that extend between a first set of opposite edges or margins while extending in a parallel relationship to each other. Such spring assemblies are desirable in that the continuous coil springs do not have to have each coil thereof individually secured as is the case with spring assemblies made from individual coil springs. To provide edge reinforcement, prior continuous coil spring assemblies have also included a double row of continuous coil springs at the second set of opposite margins. However, heretofore, it has not been possible to provide any reinforcement of the first set of opposite edges of continuous coil springs adjacent which the endmost coils of each spring are located.